Dataset Information

Hypoxia promotes glioma-associated macrophage infiltration via periostin and subsequent M2 polarization by upregulating TGF-beta and M-CSFR.

ABSTRACT: Tumor-associated macrophages (TAMs) are enriched in gliomas and help create a tumor-immunosuppressive microenvironment. A distinct M2-skewed type of macrophages makes up the majority of glioma TAMs, and these cells exhibit pro-tumor functions. Gliomas contain large hypoxic areas, and the presence of a correlation between the density of M2-polarized TAMs and hypoxic areas suggests that hypoxia plays a supportive role during TAM recruitment and induction. Here, we investigated the effects of hypoxia on human macrophage recruitment and M2 polarization. We also investigated the influence of the HIF inhibitor acriflavine (ACF) on M2 TAM infiltration and tumor progression in vivo. We found that hypoxia increased periostin (POSTN) expression in glioma cells and promoted the recruitment of macrophages. Hypoxia-inducible POSTN expression was increased by TGF-? via the RTK/PI3K pathway, and this effect was blocked by treating hypoxic cells with ACF. We also demonstrated that both a hypoxic environment and hypoxia-treated glioma cell supernatants were capable of polarizing macrophages toward a M2 phenotype. ACF partially reversed the M2 polarization of macrophages by inhibiting the upregulation of M-CSFR in macrophages and TGF-? in glioma cells under hypoxic conditions. Administering ACF also ablated tumor progression in vivo. Our findings reveal a mechanism that underlies hypoxia-induced TAM enrichment and M2 polarization and suggest that pharmacologically inhibiting HIFs may reduce M2-polarized TAM infiltration and glioma progression.

SUBMITTER: Guo X

PROVIDER: S-EPMC5348338 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Hypoxia promotes glioma-associated macrophage infiltration via periostin and subsequent M2 polarization by upregulating TGF-beta and M-CSFR.

Guo Xiaofan X Xue Hao H Shao Qianqian Q Wang Jian J Guo Xing X Chen Xi X Zhang Jinsen J Xu Shugang S Li Tong T Zhang Ping P Gao Xiao X Qiu Wei W Liu Qinglin Q Li Gang G

Oncotarget 20161201 49

Tumor-associated macrophages (TAMs) are enriched in gliomas and help create a tumor-immunosuppressive microenvironment. A distinct M2-skewed type of macrophages makes up the majority of glioma TAMs, and these cells exhibit pro-tumor functions. Gliomas contain large hypoxic areas, and the presence of a correlation between the density of M2-polarized TAMs and hypoxic areas suggests that hypoxia plays a supportive role during TAM recruitment and induction. Here, we investigated the effects of hypox ...[more]

PMID: 27602954

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Project description:ObjectiveTo investigate the role of Interleukin-34 (IL-34) in acute T cell-mediated rejection (TCMR) following renal transplantation.MethodsThe mice acute TCMR model of renal transplantation was established and identified by hematoxylin and eosin (HE) and immunohistochemistry (IHC) staining. Then, IHC staining of IL-34 was also performed to determine the expression of IL-34 in allografts. Recipients were infected with IL-34 overexpression adeno-associated virus, infection efficiency of which was estimated by enzyme linked immunosorbent assay (ELISA), Western blot, and immunofluorescence. HE and IHC staining were used to estimate the grades of TCMR. Flow cytometry was performed on lymphocytes in spleens of recipients including regulatory T cells (Tregs) and M2 macrophages. The expression of cytokines in vivo was analyzed by Mouse Cytokine Grp I Panel. Finally, Tregs and M2 macrophages were cultured in vitro and treated with IL-34 to observe the effects of IL-34 on the differentiation of the cells.ResultsThe mouse TCMR model was successfully established by HE, periodic acid shiff (PAS), CD4 and CD8 IHC staining. The expression of IL-34 was significantly decreased in allografts with TCMR. BALB/c mice were successfully infected with IL-34 overexpression adeno-associated virus. Subsequently, the grade of rejection in mice TCMR model was evaluated by HE and IHC staining according to Banff criteria. It is suggested that the grade of TCMR in IL-34 overexpressed mice was significantly decreased. IHC staining and Flow cytometry showed that the proportion of Tregs and M2 macrophages in the spleens and allografts were significantly increased in IL-34 overexpressed mice. Serum levels of interferon-gamma (IFN-γ), IL-17 and tumor necrosis factor-alpha (TNF-α) were downregulated in IL-34 overexpressed mice. Moreover, IL-34 could promote macrophage M2 polarization, while failed to promote differentiation of naïve T cells into Tregs in vitro.ConclusionOverexpression of IL-34 may attenuate the progression of TCMR episodes in allografts by increasing the polarization of M2 macrophages in the spleens and allografts, which may become a potential therapeutic strategy for TCMR.

Project description:Background—Mesenchymal stem cells (MSCs) have shown therapeutic potency for treating cardiovascular diseases, but their therapeutic efficacy shows significant heterogeneity depending on their tissue of origin. We herein sought to identify the optimal source of MSCs for cardiovascular disease therapy. Methods—Heart- and bone marrow (BM)-derived GFP+ cells positive for the MSCs marker, Nestin, were flow cytometrically sorted from 7-day-postnatal Nestin-GFP transgenic mice. To study their biological characteristics in vitro, we characterized their self-renewal capacity, multi-lineage differentiation ability, and surface markers. To investigate their therapeutic potential in vivo, we intramyocardially injected Nestin+ cells (3×105) into the infarct border zone of mice subjected to acute myocardial infarction (MI), and performed echocardiography and Masson’s-Trichrome staining at 1 and 3 weeks post-MI. We characterized gene profiles with RNA-sequencing analysis, and analyzed the putative reparative mechanism, that of Periostin-mediated M2 macrophages polarization, by immunofluorescence staining, qPCR, ELISA, and flow cytometry in vivo and in vitro. Results—In vitro, the heart- and BM-derived Nestin+ cells (Nes+cMSCs and Nes+bmMSCs, respectively) were found to possess self-renewal ability, show similar tri-lineage differentiation potentials, and express some MSCs-related surface markers. Importantly, Nes+cMSCs significantly improved cardiac function, attenuated left ventricular (LV) remodeling, and decreased infarct size in the mouse MI model, compared with Nes+bmMSCs- or saline-treated MI controls. Nes+cMSC treatment notably reduced the total number of CD68+ pan-macrophages while inducing the polarization of macrophages toward an anti-inflammatory M2 phenotype in ischemic myocardium, compared with the saline-treated MI control. Periostin, which was highly expressed in Nes+cMSCs, could promote the polarization of M2-subtype macrophages in vitro and in vivo. Finally, Periostin knockdown remarkably reduced the therapeutic effects of Nes+cMSCs, inhibiting the survival and LV remodeling of MI model mice and significantly decreasing the number of M2 macrophages at lesion sites. Conclusions—Nestin+ cMSCs have greater efficacy than Nestin+ bmMSCs for cardiac repair following acute MI, using a reparative mechanism that acts at least partly through Periostin-mediated M2 macrophage polarization.

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Hypoxia promotes glioma-associated macrophage infiltration via periostin and subsequent M2 polarization by upregulating TGF-beta and M-CSFR.

Publications

Hypoxia promotes glioma-associated macrophage infiltration via periostin and subsequent M2 polarization by upregulating TGF-beta and M-CSFR.

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